The present invention is related to a method for constructing a spherical structure, especially a radome, of part spherical elements made of a rigid plastics foam.
Radomes are used especially for protection of antennas for radar and different types of radio transmitters to protect such antennas against atmospherical disturbances which may decrease the functional performance of antenna or even destroy the antenna. As the radomes are covering the antennas in all directions, the material of the radomes necessarily will affect radio or radar waves out from the antenna as well as the opposite direction. This decreasing effect is connected especially with radomes comprising a frame work structure as the load bearing part of the radome, which structure then is cover by a shell.
Self bearing shell structures have been, assembled of a plurality of elements. Such elements also affect radio signals, but the affect is minimized by a suitable material choice. Element joints in such radomes to a certain degree affect the radio waves. Development has proved that elements made of structural foam have correct structural strength and as well as dielectric properties.
Large radomes constructed by a plurality of elements also are restricted in many ways as to choice of the element materials and structure design, connected with very strong conditions as to dielectrical functions even in different radio frequency wave bands. To fulfil such claims, shell radomes made of structural foam with low specific dielectrical values and without dielectric discontinuity in the joints, will have many advantages. Such structures, however, claim a method for construction which in practical use when assembling the radome, satisfy the claims for mechanical and dielectrical values.